First all from the French stream have seen it from the observation - only EE profiles with French as first language ever got NOI for the French stream. It is their hidden requirement (that is how they search for candidates).
It is written very vaguely on their website. But I remember when meeting people from Ontario on a big job fair, they did stated, that French shall be put as a first language
Language:
A minimum of Canadian Language Benchmark (CLB)
level 7 in French
level 6 in English
And to cool you down. there is no difference when proving your work experience in the French Stream.
They do require translation of your work contract and prove of salary or payments (either directly in your reference letter or as pay subs, remuneration contract or taxes statement from which is clear, that you were paid from the company).
The only easier part for the French stream is, that you do not have to prove 400+ CRS points.